1. Field of The Invention
The present invention relates generally to the art of preparing a dry or semi-dry sausage product, and more particularly to a method of making pepperoni. In its most preferred form, the present invention relates to the preparation of diced or sliced pepperoni, wherein the sausage is cooked without using casings and wherein the dehydrating step is performed in a spiral dryer under turbulent air.
2. Description of the Prior Art
Many different processes have been used in the prior art to manufacture cured, smoked, dried and semi-dried sausages, and many such processes are known for preparing pepperoni. In some of the prior art processes, the initial meat mixture is cured and thereafter dried or heated in air, sunlight, in drying rooms, smokehouses and the like. The cure or drying time in many of the historical processes, and some processes still being used, require many hours, days or even weeks. A wide variety of final products and qualities results from the use of age-old recipes and techniques.
Pepperoni is typically prepared by stuffing the desired meat mixture into fibrous casings and curing the resultant product for extended periods. This particular sausage is most commonly served in thin slices, with or without the casing, the casing being removed after cooking if it is removed at all. Pepperoni pizzas, for example, are sold by most pizza producers throughout the world.
One prior art attempt at reducing the time required for the preparation of such sausage products is described in U.S. Pat. No. 2,346,232 issued Apr. 11, 1944 to Pirai, et al. for "Meat Process". In this patent, semi-dried meat for food ration purposes is prepared in shorter periods than were previously required, by exposing the meat mixture to a turbulent air flow to reduce the moisture content from an original 45-85% to 20-55%. The air used in this process is at a temperature of 0.degree. C.-30.degree. C. (32.degree. F. to 86.degree. F.) and the air is moved across the meat surface at a velocity of 1-18 feet/second. The meat products discussed in this patent are produced in 1/4-11/4 inch thick layers or in ropes of 3/8-inch diameter for drying. For 3/8-inch ropes, drying is accomplished to 28% in about 8-13 hours, while the 11/4-inch layers require 13 days, still a relatively short period when compared to earlier processes. The benefits of turbulent flow are said to be increased by 40% early in the process where the air contacts a moist surface. The effect of the turbulent air flow of this patent is substantially reduced as the drying continues. For example, in one test reported in the patent, drying of 3/8-inch ropes from 55% to 40% moisture took just three hours, while a further reduction to 28% required an additional five hours. It is interesting to note that the patent does not disclose any direct relationship between the humidity of the air used in the process and the time of drying. The patent claims up to 75% relative humidity, although many of the examples use relative humidities of 20-25%, 40% and 75%. Product is held in flat trays in the examples of the patent.
Another process for preparing sausages is disclosed in U.S. Pat. No. 3,482,996 issued Dec. 9, 1996 to Christianson, et al. for "Process for Preparing Dry and Semi-Dry Sausages". In this patent, the meat compositions include dehydrated, spun, edible protein fibers or dehydrated fibrous products derived from spun, edible protein fibers to substantially reduce drying time. The fibers allegedly take up the moisture which is typically removed in the drying room.
"Preparation of Partially Dehydrated Meat Products" is discussed in U.S. Pat. No. 4,265,918 issued to Kueper, et al. on May 5, 1981. The technique discussed in this patent includes immersion of the meat product in a curing solution, followed by vacuum dehydration. The initial hydration step is to about 105-125% of the products' original weight, followed by vacuum treatment to reduce the overall product weight to 70-95% of its original weight. The process is especially well suited for sliced meat products, like bacon.
Yet another process is described in Kentor's U.S. Pat. No. 4,279,935 issued Jul. 21, 1981 for "Dry Sausage Processing With Added Acid". In this process, bactericides and bacteriostats are first added to the meat, followed by treatment with an acidic mixture to reduce the pH to about 5.7. The sausage is then heated to at least 58.degree. C. and control dried to reduce the average moisture level to about 35%. The drying time is on the order of 5-20 days.
Another well-known process is to form meat loaves, bacon analogs and the like using an extruder to form sheets of the meat mixtures. For bacon analogs, the extrusion can be of multiple layers. The sheets of meat products are cooked and then sliced, e.g. to prepare products resembling bacon and having alternating fat appearing and meat appearing layers. Examples of such processes are discussed in the following U.S. Patents: U.S. Pat. No. 5,236,731 issued Aug. 17, 1993 to Heinz Becker for "Process For The Manufacture Of Sliceable, Casing Free Sausage"; U.S. Pat. No. 4,667,369 issued May 26, 1987 to Eugene F. Felstehausen for "Extrusion Apparatus For Ground Meat"; U.S. Pat. No. 4,530,132 issued Jul. 23, 1985 to Richard C. Wagner for "Meat Loaf Forming Apparatus"; U.S. Pat. No. 4,305,965 issued on Dec. 15, 1981 to Earl J. Cheney for "Bacon And Meat Analogues"; U.S. Pat. No. 4,260,640 issued Apr. 7, 1981 to Hartmann, et al. for "Moulding Food Products"; U.S. Pat. No. 4,200,959 issued May 6, 1980 to Earl J. Cheney for "Apparatus For Forming Bacon Product Analogues And The Like"; U.S. Pat. No. 4,196,222 issued on Apr. 1, 1980 to Earl J. Cheney for "Process For The Preparation Of Meat And Bacon Analogues"; and U.S. Pat. No. 4,166,138 issued on Aug. 28, 1979 to Ziminski, et al. for "Preparation Of Bacon-Like Meat Analog".
In addition to the prior art described above, applicants are also aware that spiral conveyor equipment is known for a variety of food preparation processes. In such equipment, a food product may be frozen or heated as it moves along a conveyor which forms a number of tiers or levels within a spiral system.
An example of such a spiral system is shown in U.S. Pat. No. 4,079,666 issued Mar. 21, 1978 to Plemons, et al. for "Apparatus for Treating Baked Products In Order to Improve the Shelf Life Thereof". Pizza crusts are treated with ethyl alcohol after they have been cooled in a spiral path. The spiral cooler is advantageously used to reduce the size of the area required for cooling and for control of the temperature of the pizza crusts exiting the cooler by taking advantage of the ability to control conveyor speed and air temperature within the enclosure.
Cooking of food products using spiral devices is shown in U.S. Pat. No. 5,078,120 issued Jan. 7, 1992 to Hwang for "Cooking Oven for Slow Cooking of Food Products" and in Reissue 35,259 (originally U.S. Pat. No. 4,582,047) issued Jun. 4, 1996 to Williams for "High Humidity Steam Cooker With Continuously Running Conveyor". In the former, the cooking chamber (using steam or hot air) is divided into high pressure and low pressure areas for improving the efficient heat transfer therein. The food products discussed include chicken or poultry parts, hamburger patties, fish patties, vegetable foods and other food products which may be cooked in a predominantly steam atmosphere. In the latter patent, continuously operable spray detergent cleaning baths are used with a spiral steam cooker equipped with two separate steam sources. This patent also focuses on the cooking of meat, produce, fish or poultry with the steam pressure exceeding one atmosphere, at 100.degree. C. and 100% humidity.
While these prior art processes may have proved successful for the stated purposes, there are important steps which can still be taken in improving the quality and the manufacturing of dry or semi-dry sausages. In the present case, such an improvement is made in connection with pepperoni, especially the type of pepperoni which is to be used in large quantities for the manufacture of pizzas. The present prior art practice is to prepare the pepperoni using conventional processes employing blending, stuffing the meat mixture into casings, cooking a meat mixture, and curing, following which the product is thinly sliced. The thin slices are then placed on top of the pizza for packaging.
Because the drying and curing process requires from several days to several weeks, production capacity for a manufacturing facility is limited to the amount of space allocated to the drying process. This process is capital intensive, and requires a tremendous amount of product to be held in. process at any given period of time. These current processes require the pepperoni to be held in its casing during the curing and drying phase, thereby reducing the rate at which moisture can be removed from the product and adding to manufacturing cost. Holding the pepperoni in its casing during drying also disallows the ability to slice or dice the product prior to drying, which would increase the surface area of the product and aid in moisture removal. Accordingly, a method of manufacturing pepperoni that overcomes these disadvantages would be a significant advance in this art.